1. Field of the Invention
This invention relates to a sailing craft, and particularly to a sailing craft without a rudder which can be effectively steered.
2. Description of the Prior Art
A variety of sailboats are commercially available which can be used for recreation or competition. These sailboats can have a monohull, or multihulls, depending on the intended use. Sailboats used for competition are uniquely designed to have a minimal hydrodynamic and aerodynamic drag, a large and controllable sail surface area, and include a variety of novel control features to provide a responsive and agile craft.
Hydrodynamic drag comprises the greatest component of resistance to a sailboats' forward progress. All portions of the sailboat interfacing with the water, including the hull, keel and rudder create hydrodynamic drag. Thus, particular attention to the design of these components is provided for a sailboat. Conventionally, a rudder is implemented to help steer the sailboat, and usually resides at the stern of the hull(s). To decrease hydrodynamic drag, it is desirable to eliminate the need for a rudder while still retaining adequate control of the sailboat.
Steering a sailboat without the aid of a rudder is not a new concept. For instance, a sailboard is a popular water craft sold today which comprises a mast pivotably coupled via a ball-in-socket joint to and extending upwardly from a sailboard. Steering is accomplished by tilting the mast (with sail) fore and aft.
In U.S. Pat. No. 4,819,574, a rudderless sailboat is taught including a pair of fixed masts, and a pair of sails of approximately equal surface area, one disposed each side of the keel. The craft is steered by controlling both sails simultaneously from the cockpit area. A mechanism is used consisting of either a single rope rigged to both sails, or a steering wheel and gearbox with chain-drives, to rotate the booms at the base of each sail. To achieve steering, a mechanism differentially alters the trim angle of the two sails to cause the aeroforce exerted by the wind to increase on one sail, and to decrease the force on the other sail. In this embodiment, the keel is disposed between the sails and is fixed in relation to the hull.